When Angel goes missing in the catacombs beneath New York City, the X-Men head to investigate. Soon they discover the Morlocks are behind the abduction, but at that point they may already be too late... This issue marks the first appearance of many of the original members of the Morlocks including Callisto, Plague, Masque and Sunder. The former X-Man, Angel, is kidnapped and his girlfriend, Candy, is attacked and almost murdered. Candy manages to place a call to Professor X, though, and he sends Nightcrawler to save her - he leaves Amanda Sefton in a bath tub and goes to Warren's loft only to see a strange carrying Angel into the sewers. Later, the X-Men (Colossus, Storm, Kitty and Nightcrawler) follow the kidnappers trail into the subway and even further down, where they are attacked by strangely deformed people. Eventually, they find the Angel as a prisoner of Callisto, leader of the mutant group, the Morlocks. Callisto intends to keep Angel as her love-slave. The X-Men attack but find themselves eventually overwhelmed. In the meantime, Kitty has scouted ahead and become separated from the others. When she eavesdrops on Callisto and some of the Morlocks, one of them, named Plague, infects her with a fast-working illness. The delirious Kitty is found by the sad Morlock, Caliban, who tries to help her. Realizing that he cannot cure her, he intends to ask Callisto and Plague to help, believing then that Kitty will stay with him out of gratitude. In the meantime, Sebastian Shaw is informed by his aide, Tessa, that Emma Frost fell into a coma without any discernible reason. — Description from Comic Vine community (comicvine.gamespot.com).
